Steam Generating/SGWLC/Blowdown Flashcards
What do the J tubes help to prevent?
Water Hammer when AFW initiates
What does the flow restrictor do on each MS outlet from the SG?
- Provide plant protection, in case of MSLB, by decreasing steam flow rate to reduce RCS cooling rate.
What is P-14 permissive?
SG Hi HI Lvl at 67% on 1 SG (2/3) FWI
SG level at 64% allows feeding
What will P-14 permissive cause?
- Turbine Trip
- MFP Trip
- FWI
What enables AMSAC?
Greater than 40% Power (C-20, 2/2 Turbine first stage Impulse pressure)
What generates an AMSAC signal?
FW flow < 25% (3/4 Feed flow)
What will AMSAC actuate?
- Trips Main Turbine (30 Sec)
- Starts All 3 AFW Pumps
When do DCR-310-340 (BD isolation valves) automatically isolate?
- Phase A
- High Rad:DRA300 and DRA-353
- High Level in Flash Tank
- AFW Flow Conservation / Pump Starts
Where do we drain both flash tanks to?
- TRS Overflow via DRV-350
When do BD sample isolation valves (DCR-301-304) automatically close?
- High Rad
- Phase A
What actuations does a high rad signal from DRA-300 cause?
- Closes BD Isolation DCRs 310-340
- Closes DRV-350 SGBD Flashtank to TRS
- Closes BD Sampling DCRs 301-304
What actuations does a high rad signal from DRA-353 cause?
- Trips SGBD Treatment Pump
- Closes BD Isolation DCRs 310-340
- Closes DRV-350 SGBD Flashtank to TRS
- Closes BD Sampling DCRs 301-304
Control air header pressure is lowering at a fast rate. At 80 psi, the reactor is manually tripped, and header pressure continues to lower. What will happen to the air reg valves in the BD system if pressure continues to lower?
All air reg valves on BD system will isolate on loss of ctrl air
- DRV-350/352
- BD isolation valves
- BD Flow Ctrl Valves
- BD Sample Valves
What is the cooling water to the BD Hx and flash tank quenching?
Containment Chill Water
What supplies cooling to the BD sample Hx?
CCW
What does SGWLC maintain?
SG Narrow Range level at 43.8% for all power levels
What plant protection functions do the SG pressure transmitters provide?
- SG Steam Line Break Detection
- SI Initiation
- Main Steam Line Isolation
- Low Steam pressure Alarms
What is the dominant control for SG Level?
Level Dominant (43.8%)
- Steam Generator Level overrides Feed flow/Steam Flow mismatch over time, level is a lag signal
What causes a Steam Line Isolation (SLI)?
- Cnt # High-High at 2.8# (2/4)
- SG # low < 500# (1/1 on 2/4 SG)
- High Stm flow with P-12 (1.42E6/1.6E6) (1/2) on 2 SG
What is density compensation?
Converts volumetric flowrate of steam to mass flowrate for input into SGWLC circuit
(Left 2 Channels)
Where do we measure SG Level?
SG Downcomer
What is swell caused by?
An increase in steam flow
(which will cause an increased indication of SG lvl in the downcomer due to decreased SG pressure)
What is shrink caused by?
A Reduction in steam flow
(which will cause an decreased indication of SG lvl in the downcomer due to a rise in SG pressure)
In MODES 1 and 2, the reactor is critical and thus has the potential to produce maximum THERMAL POWER. Thus, to ensure that the assumptions of the accident analyses remain valid, all RCS loops are required to be OPERABLE and in operation in these MODES to prevent (what 2 things)
DNB and Core Damage
What constitutes an OPERABLE RCS Loop in Modes 1 and 2?
An OPERABLE RCP in operation providing forced flow for heat transport and an OPERABLE SG
With the plant in MODE 3 and the CRDM’s energized, how many RCS loops are required to be operable?
2 RCS loops shall be OPERABLE with BOTH in Operation
What is the maximum permissible RCS to SG leakage? (TS 3.4.13)
150 gpd primary to secondary LEAKAGE through any one steam generator (SG)
Basis: Limit release to atmosphere outside ctmnt based on 10CFR100
If the controlling channel STEAM flow fails high, what will happen the FRV?
The FRV will go open because Feed Flow will want to match Steam Flow
If the controlling channel STEAM flow fails low, what will happen the FRV?
The FRV will go closed because Feed Flow will want to match Steam Flow
If the controlling channel FEED flow indication fails low, what will happen the FRV?
The FRV will go open because Feed Flow will want to match Steam Flow
If the controlling channel FEED flow indication fails high, what will happen the FRV?
The FRV will go closed because Feed Flow will want to match Steam Flow
With the plant in MODE 3 and the CRDM’s are not energized, how many RCS loops are required to be operable?
2 RCS loops shall be OPERABLE with one in operation
What, with respect to RCS Loops, is required to be operable in Mode 4? (TS 3.4.6)
Two loops consisting of any combination of RCS loops and residual heat removal (RHR) loops shall be OPERABLE, and one loop shall be in operation.
Basis:
Accidental boron dilution event
What does TS 3.4.7 (RCS Loops Mode 5) require?
-1 RHR loop shall be OPERABLE and in operation,
AND
- a. 1 additional RHR loop shall be OPERABLE;
OR
b. The secondary side water level of at least 2 SGs shall be above the lower tap of the SG wide range level instrumentation by greater than or equal to 420 inches.
Basis:
Accidental boron dilution event
What will happen if either the SG Level or Flow Controllers are lost?
The RU will instantly go to manual to maintain the FRV at its current position
Unit 1 was operating at 100% power when a loss of main feedwater occurs to a single SG due to the failure of the controlling feedwater flow instrument.
A valid indication on the affected SG “Flows / Level / Pressure” recorder for this failure would be a rapidly lowering SG level and a?
high feedwater flow indication on the feedwater flow pen
What will cause a FWI?
- SG High-High level (P-14) (67% NR 2/3 on 1 SG)
- SI
- Rx trip (P-4) with low Tavg (Tavg less than 554°F on 2/4 loops)
What happens on a High High SG Level of 67%?
- FWI
- Turbine Trip
- MFP Trip
Can chemistry override the High Radiation signal that made the sample valves closed?
YES
High Level in a Blowdown Flash Tank will…
Close Blowdown Isolation DCRs 310 through 340
Low Level in a Blowdown Flash Tank will…
- Trip SGBD Treament Pump
- Close DRV-350 SGBD Flashtank to TRS
Why does a failure of the SG Pressure input affect that SGs SF channel?
Because the steam flow channels are density compensated
What is the basis for TRM 8.7.1, SG Temperature and Pressure Limits
prevent brittle fracture
